The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

An armed robber in the US has been arrested and charged with a string of offences, including attempted murder, after his sidearm malfunctioned at the worst possible time during what could have been a very bloody hold-up.

Concealing his identity with a hood, Aaron Christopher King of McKinleyville marched into a California bottle shop earlier this week, cut in front of another customer and shoved a gun over the counter, which the worker quickly tried to bat away.

King fumbled with the weapon for a moment, before managing to rip the slide back and pull the trigger.

Fortunately for the clerk, instead of a loud bang, the gun elicited only a flaccid click, prompting King to fiddle with the useless chunk of metal. Seizing his opportunity, the cashier snatches the coin tray out of the register and starts trying to whack his assailant with it.

King then appears to abandon any serious attempt to see the stick-up through.

Two customers rushed to the checkout boy's aid and the trio was able to subdue the blundering crook until police arrived. As North Coast News reports King was charged with robbery, attempted murder, and assault with – and possession of – a firearm.